[asterisk-dev] Reducing RTP overhead

[Paul Cadach]

Hi,

John Todd wrote:
[skipped]
> There is the protocol called RTPC (RFC2508) which is rumored to
> compress ~40 byte IP/UDP/RTP headers down to <5 bytes when used with
> RFC2509.  I haven't seen it in in action other than on T1 connections
> point-to-point, and I don't know what the requirements are for
> intermediate systems to understand and route the IP layer datagrams
> with the shortened packet data.  I have only been a witness to what I
> was told was a compressed link, and I've not actually set it up
> myself.  Cisco seems to be the only player in this field currently,
> though it is an open standard.

This protocol usually named as cRTP, compressed RTP, not as RTPC nor RTCP.
Because cRTP is not self-contained protocol (it's just like another way of
embedding RTP packets into IP), so there is no way to have negotiations of
between hosts, and usage of cRTP should be configured on full path between
cRTP-aware routers, otherwise it will not work correctly.


WBR,
Paul.